Sounds like theres still remnants in your system that need to be manually removed.
You can also permanently disable the check for signed drivers using this program http://www.ngohq.com/home.php?page=dseo The instructions are included and is pretty straight forward. Run the Dseo.exe file and enable test mode, then sign driver.
every time i boot up i get this error 1st it shows marvell adapter then it says no hard disk detected!! then this screen comes up. c\Windows\system32\drivers\sfsync04.sys it gives me an error about digitally signed driver error? it all started when i installed toca race driver 3,i removed the game and the problem still persists? the only way i can boot up is to after hitting enter to continue when this error appears and then hitting f8,and then hitting the disable check for digitally signed drivers.i have windows vista home ultimate 64bit,intel i7quad core,6gb ram.gef 285 vid card,i can get the model #'s if it helps i don't know what other info i need to give? if you guys need more let me know i will provide,thank you in advance for taking the time to read this and trying to help,this old man appreciates it believe me other than this the computer runs great no problems at all??